1. Technical Field
Various embodiments generally relate to a semiconductor apparatus, and more particularly, to data reception of a semiconductor apparatus.
2. Related Art
A semiconductor apparatus includes a data receiver to receive data from outside. The semiconductor apparatus operates in synchronization with a clock signal in order to operation at high speed, and the data receiver also latches data applied from outside in synchronization with the clock signal.
FIG. 1 is a diagram illustrating a data receiver of a conventional semiconductor apparatus.
The data receiver 2 latches external data DATA applied through a data input/output pad 1 as internal data DATA_RX in synchronization with a data latch clock signal CLKOUT.
Recently, a DDR (Double Data Rate) synchronous semiconductor apparatus has been used to further improve operation speed. When the DDR synchronous semiconductor apparatus is used, data is latched even at a falling edge as well as a rising edge of a clock signal. According to the DDR synchronous semiconductor apparatus, the data receiver 2 may receive data quickly by latching external data DATA at a falling edge as well as a rising edge of a data latch clock signal CLKOUT.
Additionally, in order for the semiconductor apparatus to normally operate, the external data DATA must be precisely latched. For this operation, the phase of the data latch clock signal CLKOUT must be controlled to precisely latch data.